In 1936, Kilgallen competed with two other New York newspaper reporters in a race around the world using only means of transportation available to the general public. She was the only woman to compete in the contest and she came in second.[5] She described the event in her book Girl Around The World, which is credited as the story idea for the 1937 movie Fly-Away Baby starring Glenda Farrell as a character partly inspired by Kilgallen.[3] During a stint living in Hollywood in 1936 and 1937, Kilgallen wrote a daily column primarily read in New York [6][unreliable source?] that nonetheless provoked a libel suit from Constance Bennett,[7][unreliable source?] "who in the early thirties had been the highest paid performer in motion pictures," according to a Kilgallen biography, "but who was [in 1937] experiencing a temporary decline in popular appeal."[8][unreliable source?]

Back in New York in 1938, Kilgallen began writing a daily column, the Voice of Broadway, for Hearst's New York Journal American, which the corporation created by merging the Evening Journal with the American.[5] The column, which she wrote until her death in 1965, featured mostly New York show business news and gossip, but also ventured into other topics such as politics and organized crime. The column eventually was syndicated to 146 papers via King Features Syndicate.[2][3] She also had a radio program, Voice of Broadway, which was broadcast on CBS during World War II.[9]

On April 6, 1940, Kilgallen married Richard Kollmar (1910–1971) who had starred in the musicals Knickerbocker Holiday and Too Many Girls.[10][11] Beginning in April 1945, Kilgallen and Kollmar co-hosted a WOR-AM radio talk show, Breakfast With Dorothy and Dick, from their 16-room apartment at 640 Park Avenue. The show followed them when they bought a Neo-Georgian brownstone at 45 East 68th Street in 1952.[12] The radio program, which like Kilgallen's newspaper column mixed entertainment with serious issues, remained on the air until 1963.[13]

Kilgallen was among the notables on the guest list of those who attended the coronation of Queen Elizabeth in 1953. Kilgallen's articles won her a Pulitzer Prize nomination during this era.[5]

In 1950, Kilgallen became a panelist on the American television game showWhat's My Line?, which was aired on the CBS television network from 1950 to 1967. She remained on the show for 15 years, until her death.[5] Fellow panelist Bennett Cerf claimed that, unlike the rest of the panel members, whose priority was getting a laugh and entertaining the audience, Kilgallen was interested mainly in guessing the correct answers. Cerf asserted that she also would extend her time on camera by asking more questions than necessary, the answers to which she knew would be affirmative.[14]

Cerf said after Kilgallen's death that she had had a conservative point of view, that of a "Hearst girl," which differed from the views of himself and other panelists. He added that all four panelists shared a dressing room every Sunday, and Kilgallen published in her column information that her colleagues had revealed in their weekly conversations.[15] Cerf, speaking for his fellow panelists, the panel moderator, and himself in an audio-tape-recorded interview at Columbia University two years and two months after Kilgallen's death, said, "We didn't like that."[15]

In 1958, Kilgallen and her husband Kollmar, along with Albert W. Selden, co-produced a musical on Broadway entitled, The Body Beautiful.[16] Kilgallen and her fellow panelists made mention of the show on various episodes of What's My Line? during this time period. On one episode, a cast member of the ill-fated musical (a well-built young man, billed as a "chorus boy" in the episode) appeared as a contestant and stumped the panel.

Though Kilgallen and Frank Sinatra were fairly good friends for several years and were photographed rehearsing in a radio studio for a 1948 broadcast, they had a falling out after she wrote a multi-part 1956 front-page feature story "The Frank Sinatra Story". Thereafter their relationship was publicly acrimonious.[17][18]

Kilgallen covered the 1954 murder trial of Dr. Sam Sheppard.[5] The New York Journal American carried the banner front-page headline that she was "astounded" by the guilty verdict because of what she argued were serious flaws in the prosecution's case.[19] The doctor, whose specialty was osteopathicneurosurgery,[20] was convicted of bludgeoning his wife to death at their home in the Cleveland suburb of Bay Village.

At the time Kilgallen's sharp criticism of the verdict was controversial and a Cleveland newspaper dropped her column in response.[21][22][23] Nine years and some months after the jury returned a guilty verdict for Dr. Sheppard, she revealed publicly, at an event that was held at the Overseas Press Club in New York, that the judge had told her toward the beginning of the trial that Dr. Sheppard was "guilty as hell."[24]

Kilgallen was publicly skeptical of the conclusions of the Warren Commission's report into the assassination of President Kennedy and wrote a number of articles on the subject.[25] Later she obtained a copy of Jack Ruby's testimony to the Warren Commission, which was published on the front pages of the Journal American,[26] the Philadelphia Inquirer,[27] the Seattle Post Intelligencer,[28] and other newspapers. Most of that testimony did not become officially available to the public until the commission released its 26 volumes of hearings and exhibits in November 1964, around the time of the first anniversary of the assassination.[29]

After her death, noted conspiracy theorist Penn Jones, Jr. claimed that Kilgallen had conducted an interview with Jack Ruby inside the Dallas courthouse where he was tried for the shooting death of Lee Harvey Oswald, without ever revealing the subject of their purported conversation. However, Jones never cited any sources or corroborating evidence in support of his claims. Moreover, Jones' assertion was vehemently denied by a number of persons who would normally have had knowledge of such an interview, including then Assistant Dallas D.A. Bill Alexander who characterized Jones' claim of an interview as "bull shit." Then-sheriff Bill Decker and Pulitzer Prize winning reporter Hugh Aynesworth also dismissed Jones' claim as fiction.[32]

Jones made the alleged Jack Ruby interview the basis of a claim that Kilgallen was murdered in order to silence her before she could release supposedly explosive information about the Kennedy assassination. However, as with the claimed interview itself, this assertion has been widely dismissed. No evidence of murder has ever been produced. Kilgallen was known as a heavy drinker, according to Aynesworth.[32] The New York City medical examiner's office stated her death was likely a case of mixing barbiturates with a dangerous level of alcohol. The death certificate includes the words "circumstances undetermined."[33] The editor of Ramparts Magazine, a far left publication with a history of promoting conspiracy theories, and which gave considerable coverage to the unsourced Jones claims, felt obliged to add the disclaimer on the page it devoted to Kilgallen in the November 1966 edition: "We know of no serious person who really believes that the death of Dorothy Kilgallen was related to the Kennedy assassination."[32]